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Gingiva and Periodontal Tissue Regeneration
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Avita Rath, Preena Sidhu, Priyadarshini Hesarghatta Ramamurthy, Bennete Aloysius Fernandesv, Swapnil Shankargouda, Sultan Orner Sheriff
Among these cells, the first three types are responsible for regenerating the periodontal tissue, while the last type—i.e., epithelial cells—are responsible for soft tissue regeneration. It is worth mentioning that the higher migration rate of epithelial cells (10 times faster) in comparison to the other periodontal cell types is the reason for observing the formation of the long junctional epithelium in the periodontal therapy (Engler et al. 1966). Infiltration of epithelial cells inside the defect can promote repair by the formation of an unusual architecture with a loss of function (Caton et al. 1987). Therefore, guided tissue membranes are implanted to limit the infiltration of the epithelial cells (Nyman et al. 1987). If epithelial cells are ruled out from the wound, other cell types with regenerative potential are thus allowed to become established, and epithelial down-growth can be successfully prevented (Linde et al. 1993). A combination of bonegraft materials, promoting the migration and differentiation of osteoblast cells, and GTR is the most commonly-used approach for achieving an optimal periodontal regeneration (Frost 1989a; Frost 1989b). Two reasons have been identified behind this synergic activity, i.e., the biological effects of bone grafts and the `Melcher hypothesis’, which explains the importance of cells used for the periodontal regeneration. According to this hypothesis, the origin of cells dictates the nature of the attachment in periodontal healing and the complete periodontal regeneration may be achieved when we apply cells with an origin from the periodontal ligament and the perivascular bone cells (Aurer and Jorgie-Srdjak 2005; Koop et al. 2012).
Hard Tissue Replacements
Published in Joyce Y. Wong, Joseph D. Bronzino, Biomaterials, 2007
Sang-Hyun Park, Adolfo Llinás, Vijay K. Goel, J.C. Keller
Junctional epithelium: The epithelial attachment mechanism which occurs with teeth, and has been observed infrequently with implants by some researchers. Less than 10 cell layers thick, the hemidesmosomal attachments of the basal cells to the implant surface provide a mechanical attachment for epithelium and prevent bacterial penetration into the sulcular area.
Dental Implant Infection: Typical Causes and Control
Published in Huiliang Cao, Silver Nanoparticles for Antibacterial Devices, 2017
Peri-implant mucosa is composed of well-keratinised oral epithelium, sulcular epithelium and junctional epithelium, as well as underlying connective tissue (Berglundh et al. 1991). The oral gingival epithelium faces the oral cavity and the oral sulcular epithelium faces the implant surface without contact. The histological construction of the peri-implant oral gingival epithelium is generally comparable with the marginal periodontium. It is a multilayered squamous epithelium, which can be divided into the following layers (Listgarten 1972): stratum basale (with cylindrical or cubical mitotic active cells), stratum spinosum, stratum granulosum and stratum corneum. In general, the junctional epithelium on the implant with a length of approximately 2 mm appeared to have an expansion comparable to a tooth. It was further observed that the junctional epithelium takes on a stable position under an inflammation-free condition and ends approximately 1 mm above the crestal bone level. Between the implant surface and the epithelial cell are hemidesmosomes and internal basal lamina comparable to a tooth surface. It can be seen from animal experiments that, on the surfaces of titanium and epoxy resin, as well as in the area of the abutment of aluminium oxide ceramic, a junctional epithelium was formed. The soft tissue interface is made up of the epithelium and the underlying connective tissue, which includes the biologic zone known as the biologic width, referring to the height of the dentogingival attachment apparatus encircling the tooth. The term biologic width is based on the work of Gargiulo et al. (1995), who described the dimensions of the dentogingival junction in human cadavers. The average dimension of 2.04 mm (1.07 ± 0.97 mm) is composed of supra-alveolar connective tissue and junctional epithelial attachment. In analogy with a tooth, the dentogingival complex additionally contains part of the gingival sulcus. Berglundh and Lindhe were able to show in an animal study that a supracrestal implant surface with an apical coronal expansion of at least 3 mm is necessary for the development of a stable biological width. Functionally, in a clinical sense, there must not be any encroachment within 2 mm of the bone that surrounds the tooth (Dhir et al. 2013). However, a crestal peri-implant bone resorption must be expected below this distance. This, again, could be beneficial for peri-implant plaque accumulation in the exposure of structured implant surfaces.
Recent advances in polymer scaffolds for biomedical applications
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Deepika Sharma, Sampa Saha, Bhabani K. Satapathy
Current research aims at designing scaffolds to prevent Periodontitis and all periodontal diseases are caused due to bacterial infections that destroy the fibrous tissues and bones supporting the teeth, which may lead to tooth loss if left untreated [164]. Periodontal therapy aims at arresting periodontal disease progression along with the regeneration of lost and damaged structures. Conventionally, open flap debridement (OFD) was being used, but it resulted in the formation of a long junctional epithelium and asymmetrical periodontal regeneration if left empty after OFD. Currently, barrier membranes are being designed for regenerative therapies, GTR/GBR, to prevent epithelial cells and fibroblasts from occupying the defected space, by facilitating sequential periodontal regeneration. Currently, bone grafts were used for the regeneration of the alveolar bone cementum but lack systematic regeneration of gingiva (gum) and periodontal ligament. Thus, regenerative medicine has now discovered engineered nanofiber scaffolds as potential structures for enhancing the regeneration process as they provide high surface area, surface functionalization potential, and tunability of porosity from micro- to nanoscale for closely mimicking the surface morphology of natural ECM [46, 54]. Nowadays, researchers are focused on studying the influence of electrospun fibers in cellular therapies, origins of the stem and progenitor cells, amongst adult organisms and thereby contributing to the development of improved biomaterials [260,261]. Some of the recent advancements in designing modified polymeric EMs for applicability in dental tissue regeneration are summarized in Table 4.
Triethylene glycol dimethacrylate: adjuvant properties and effect on cytokine production
Published in Acta Biomaterialia Odontologica Scandinavica, 2018
Sara Alizadehgharib, Anna-Karin Östberg, Ulf Dahlgren
Dental composite resins, which are biomaterials that are used to replace biological tissues in both appearance and function, consist of inorganic filler particles and an organic matrix of acrylate/methacrylate polymers [1]. The organic component may contain any of several different acrylate/methacrylate monomers, although one of the most commonly used monomer is triethylene glycol dimethacrylate (TEGDMA) [1–3]. TEGDMA improves the bonding strength and viscosity of the resin composite [4]. After curing, the composite material contains unreacted monomers, which may be released into the oral cavity and/or diffuse through the dentin into the pulp [5–7]. Previous studies have shown that the concentration of TEGDMA that reaches the pulp could be about 4 mmol/L [8]. The leakage of the monomers is time-dependent, and about 90% of the unreacted monomers are released in the first 24 h post-polymerization [9]. The monomers may come in contact with leukocytes that are present in the pulp and oral cavity. The population of white blood cells found in the dental pulp consists of CD4+ and CD8+ T lymphocytes, as well as dendritic cells (DCs), neutrophils and macrophages [10]. Gingival crevicular fluid (GCF) flows into the gingival crevice through the junctional epithelium thereby transporting cells into the oral cavity. The population of cells in the GCF comprises 95–97% neutrophils, 2–3% monocytes 1–2% and lymphocytes, with fewer T cells than B lymphocytes [11]. Since many different cells are present in the oral cavity, pulp and epithelium, a variety of cells may encounter free monomers. It is therefore important to study the different effects that the monomers may have on the cells.